For example, in a vehicle, a handle device to be gripped by the passenger is provided to in-vehicle wall surfaces of a passenger seat and backseats. The handle device includes a grip portion provided rotatably, a spring portion arranged to urge the grip portion in a given rotational direction, and a damper arranged to damp the rotation of the grip portion.
For example, JP-2002-221247-A discloses an assist grip device including a rotary damper. This rotary damper includes a housing having an annular groove, a rotor having a main portion to be inserted into the annular groove and relatively rotatable to the housing, silicone oil filled in the annular groove, and sealing members for sealing the space between the rotor and the housing.
In JP-2002-221247-A, silicone oil is filled in the annular groove. In the annular groove, bubbles may be left in the silicone oil when being filled, or bubbles may enter the annular groove when the silicone oil leaks due to thermal expansion. When the bubbles spread in the annular groove at the time of relative rotation of the housing and the rotor, resistance by silicone oil cannot be obtained at the part where the bubbles spread, thereby reducing the torque to be produced by the damper. Since the annular groove is sealed in order to prevent leakage of the silicone oil, it is difficult to remove the bubbles after the damper has been assembled.